Using
the jar-signing-alias Deployment Property

The asadmin
deploy command property jar-signing-alias specifies
the alias for the security certificate with which the application
client container JAR file is signed.

Java Web Start won't
execute code requiring elevated permissions unless it resides in a
JAR file signed with a certificate that the user's system trusts.
For your convenience, GlassFish Server signs the JAR file automatically
using the self-signed certificate from the domain, s1as.
Java Web Start then asks the user whether to trust the code and displays
the GlassFish Server certificate information.